1. Field of the Invention
This invention lies in the field of smokeless burning of waste gases in flare stacks.
More particularly, it concerns the injection of high velocity jets of steam radially inwardly and upwardly into the column of gas flowing above the tip of the flare stack, for mixing with the gas, for creating a chemical atmosphere to improve the smokeless combustion of the gas.
Still more particularly, this invention involves the use of nozzles for injection of steam at at least two different elevations above the tip of the flare stack. Half of the nozzles are at a low selected elevation above the tip, and the other half are at a higher elevation above the tip. Sequential circumferential jets being low and high.
2. Description of the Prior Art
It is common in the art of smokeless flaring of vented glass, for steam injection into the gas column below the burning zone and above the flare discharge point or tip of the stack, for the purpose of suppression of smoke, as the gas is burned in the atmosphere. The gas is entrained or mixed with the steam. The effectiveness of smoke suppression, and the efficiency of smoke suppression, in point of the steam-to-gas weight ratio, depends upon the completeness of steam-gas mixture prior to burning of the flare gas.
In the present state of the art of smokeless flaring, U.S. Pat. No. 2,779,399 is typical, while U.S. Pat. No. 3,134,424 represents an effort to improve the gas-steam mixture condition through the use of plural steam ports per steam injection device, where the flow paths of steam from each of the ports may deviate angularly from the horizontal plane, as well as from a line between flare tip center line and the center line of the steam tip, to distribute steam, at the expense of gas access to steam, as discharged. In U.S. Pat. No. 2,779,399 the steam discharge is both radially inwardly and at the same level above the flare tip in circumerential spacing above and about the tip. In U.S. Pat. No. 3,134,424, the device shows mixture advantage of the port arrangement for the steam tip and varying steam discharge levels above the flare tip where adjacent and equivalent orifices were at the same elevational level above the flare tip. However, the mixture advantage obtained was less than satisfactory as a final condition because the steam, as it travels forward from the ports, is denied suitable access to the gas stream. In other words, the gas flow was occluded by the steam flow.